A Steam Community Group Announcement reveals a long-term partnership for DiRT Rally with the FIA World Rallycross Championship. This trailer celebrates the news, and here's word on what this will soon bring to the Early Access racing title:

Owners of the game will soon be able to drive a selection of these monstrous cars for themselves across three different game modes and experience the sheer speed, action, dynamism and performance that makes World RX one of the fastest growing motorsports in the world. As with all previous updates, this new content will be available free of charge to existing and included for new owners of the game.